docs: def _get_site_scaling(self, C, pga_rock, sites, period, rjb):
          """
          Returns the site-scaling term (equation 5), broken down into a
          linear scaling, a nonlinear scaling and a basin scaling term
          """
          flin = self._get_linear_site_term(C, sites.vs30)
          fnl = self._get_nonlinear_site_term(C, sites.vs30, pga_rock)
          fbd = self._get_basin_depth_term(C, sites, period)
          return flin + fnl + fbd